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  • What type of malware can reside in windows restore?

    - by qwertymk
    I was reading aking1012's comment on How to create Windows Vista/Windows 7 Startup disk or Rescue disk or system restore points on a CD? . He says that: The first thing I usually do is disable system restore. Some REALLY nasty malware hides in there and is very difficult to delete. As far as rescue media, I make a full backup image. It doesn't directly address the question so it's a comment not an answer, but I thought it was worth noting What type of malware can hide there, and how is that possible as the restore info must be stored with a checksome to make sure it's not modified, right?

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  • How can I verify the integrity of a WAN connection?

    - by Nic Waller
    We have two scanners in our branch office which upload images to the head office via FTP. In the last week, both scanners have started delivering a lot of corrupted images. I suspect that the problem may be with the WAN link, and that TCP might not be detecting/correcting all errors. Is there any software for Windows that allows me to test the integrity of the connection by sending packets with an embedded CRC?

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  • Software that will burn DVDs with a SFV or Pararchive file for each disc?

    - by Matt
    I'd like to burn several thousand RAW files (.DNG) of around 10-30 MB each to DVD to backup my photo archive. I'm looking for software that can do this and include an SFV-type file on each disc burnt. These are my requirements: compression is optional, and probably not desirable due to the extra time involved files should be spread amongst the discs as self-contained units, i.e. I don't want to have to load files from more than one disc to be able to read the files on that disc, so that excludes WinRAR's spanning options I don't want to spend time writing ISO images first as this will be a task I'll need to repeat often as I add new images to my archive - the software should write to the DVDs for me as simply as possible I'd like the SFV/Pararchive/recovery record to be stored with the files on each disc, so it only references the files on that particular disk Thanks in advance!

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  • How can I copy files to an external drive and verify their integrity in OS X?

    - by jedavis
    I'm moving large amounts of data from one external drive to another larger one. The files are important and the smaller drives need to be cleared and reused (HD camera). Is there some utility for moving files and verifying their integrity? I've been using this command find . -type f -exec md5 '{}' \; > md5list.txt in the terminal to create a list of MD5s for each file then using diff to compare the two. However, I am moving 320GB at a time, which takes a while by itself. Computing the checksums takes another hour or so. It would be much more efficient to do this on the fly, during the copy. I'm just hoping someone has already written the software...

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  • File corruption (bad checksums) in large files copied to VMware guest

    - by AllanA
    In setting up a development lab, I've got a desktop system running ESXi 4.1.0 (free license) on SATA RAID 0 (already purchased and configured when I started this job; I'm open to hardware input as it pertains to my problem.) Its guests so far include two Win2008 Server R2 64-bit VMs and on Ubuntu 10.04 64-bit VM. I'm installing onto the Windows servers. We've been copying off some fairly large files (over a gigabyte) for an installation, hoping to install more quickly from a (virtual) hard drive than from the network for from BD-ROM. The problem is that they keep coming up with different checksums from the originals. The file sizes are the same, but md5sum reports different numbers (and so does the installer, as it refuses to continue when the checksums don't match.) I've tried copying directly from the BD-ROM (attaching the OS drive to the host system's physical drive). I've tried copying the large files onto a co-worker's Windows machine from his Blu-Ray drive; when I do that, the checksums match. But when I copy from his machine to the VM guest over a network share, the checksums no longer match. Thinking this meant a corrupt destination drive, I deleted it in vSphere and added another freshly created drive. The problem persists. I'm not sure what to try next.

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  • Windows File Checksums - Is my system hacked?

    - by rism
    I would like to know if there is a utility to verify the checksums of every windows file on my Win 7 Ultimate system. It seems on the surface such an obvious utility but I dont ever remember seeing one? I had a very weird experience while surfing earlier today and now Im not entirely sure my system is secure. I have a collection of tools in the WSCC suite but these tools no doubt just make system calls to the win32 api and if that has been subverted then the tools are practically useless. How do I know my Win 7 files are actually Win 7 files? I am particularly interested in verifying the integrity of all network TCP/IP files.

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  • How to generate a random unique string with more than 2^30 combination. I also wanted to reverse the process. Is this possible?

    - by Yusuf S
    I have a string which contains 3 elements: a 3 digit code (example: SIN, ABD, SMS, etc) a 1 digit code type (example: 1, 2, 3, etc) a 3 digit number (example: 500, 123, 345) Example string: SIN1500, ABD2123, SMS3345, etc.. I wanted to generate a UNIQUE 10 digit alphanumeric and case sensitive string (only 0-9/a-z/A-Z is allowed), with more than 2^30 (about 1 billion) unique combination per string supplied. The generated code must have a particular algorithm so that I can reverse the process. For example: public static void main(String[] args) { String test = "ABD2123"; String result = generateData(test); System.out.println(generateOutput(test)); //for example, the output of this is: 1jS8g4GDn0 System.out.println(generateOutput(result)); //the output of this will be ABD2123 (the original string supplied) } What I wanted to ask is is there any ideas/examples/libraries in java that can do this? Or at least any hint on what keyword should I put on Google? I tried googling using the keyword java checksum, rng, security, random number, etc and also tried looking at some random number solution (java SecureRandom, xorshift RNG, java.util.zip's checksum, etc) but I can't seem to find one? Thanks! EDIT: My use case for this program is to generate some kind of unique voucher number to be used by specific customers. The string supplied will contains 3 digit code for company ID, 1 digit code for voucher type, and a 3 digit number for the voucher nominal. I also tried adding 3 random alphanumeric (so the final digit is 7 + 3 digit = 10 digit). This is what I've done so far, but the result is not very good (only about 100 thousand combination): public static String in ="somerandomstrings"; public static String out="someotherrandomstrings"; public static String encrypt(String kata) throws Exception { String result=""; String ina=in; String outa=out; Random ran = new Random(); Integer modulus=in.length(); Integer offset= ((Integer.parseInt(Utils.convertDateToString(new Date(), "SS")))+ran.nextInt(60))/2%modulus; result=ina.substring(offset, offset+1); ina=ina+ina; ina=ina.substring(offset, offset+modulus); result=result+translate(kata, ina, outa); return result; } EDIT: I'm sorry I forgot to put the "translate" function : public static String translate(String kata,String seq1, String seq2){ String result=""; if(kata!=null&seq1!=null&seq2!=null){ String[] a=kata.split(""); for (int j = 1; j < a.length; j++) { String b=a[j]; String[]seq1split=seq1.split(""); String[]seq2split=seq2.split(""); int hint=seq1.indexOf(b)+1; String sq=""; if(seq1split.length>hint) sq=seq1split[hint]; String sq1=""; if(seq2split.length>hint) sq1=seq2split[hint]; b=b.replace(sq, sq1); result=result+b; } } return result; }

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  • How come ftp protocol produces transmission errors sometimes if the data is using TCP, which is checksummed?

    - by Cray
    Every once in a while, downloading (especially large) files through ftp will produce errors. I am guessing that's also partly the reason why all major sites are publishing external checksums along with their downloads. How is this possible if ftp goes through TCP, which has checksum inbuilt and resends data if it is transmitted corruptly? One could argue that this is due to the short length of the CRC in the TCP protocol (which is 16bit I think, or something like that), and the collisions are simply happening too often. but 1) for this to be true, not only must there be a CRC collision, but also the random network error must modify both the CRC in the packet, and the packet itself so that the CRC will be valid for the new packet... Even with 16 bitCRC, is that so likely? 2) There are seemingly not many errors in, say, browsing the web which also goes through TCPIP.

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  • Creating a unique key based on file content in python

    - by Cawas
    I got many, many files to be uploaded to the server, and I just want a way to avoid duplicates. Thus, generating a unique and small key value from a big string seemed something that a checksum was intended to do, and hashing seemed like the evolution of that. So I was going to use hash md5 to do this. But then I read somewhere that "MD5 are not meant to be unique keys" and I thought that's really weird. What's the right way of doing this? edit: by the way, I took two sources to get to the following, which is how I'm currently doing it and it's working just fine, with Python 2.5: import hashlib def md5_from_file (fileName, block_size=2**14): md5 = hashlib.md5() f = open(fileName) while True: data = f.read(block_size) if not data: break md5.update(data) f.close() return md5.hexdigest()

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  • construct a unique number for a string in java

    - by praveen
    We have a requirement of reading/writing more than 10 million strings into a file. Also we do not want duplicates in the file. Since the strings would be flushed to a file as soon as they are read we are not maintaining it in memory. We cannot use hashcode because of collisions in the hash code due to which we might miss a string as duplicate. Two other approaches i found in my googling: 1.Use a message digest algorithm like MD5 - but it might be too costly to calculate and store. 2.Use a checksum algorithm. [i am not sure if this produces a unique key for a string- can someone please confirm] Is there any other approach avaiable. Thanks.

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  • Script to copy files on CD and not on hard disk to a new directory

    - by John22
    I need to copy files from a set of CDs that have a lot of duplicate content, with each other, and with what's already on my hard disk. The file names of identical files are not the same, and are in sub-directories of different names. I want to copy non-duplicate files from the CD into a new directory on the hard disk. I don't care about the sub-directories - I will sort it out later - I just want the unique files. I can't find software to do that - see my post at SuperUser http://superuser.com/questions/129944/software-to-copy-non-duplicate-files-from-cd-dvd Someone at SuperUser suggested I write a script using GNU's "find" and the Win32 version of some checksum tools. I glanced at that, and have not done anything like that before. I'm hoping something exists that I can modify. I found a good program to delete duplicates, Duplicate Cleaner (it compares checksums), but it won't help me here, as I'd have to copy all the CDs to disk, and each is probably about 80% duplicates, and I don't have room to do that - I'd have to cycle through a few at a time copying everything, then turning around and deleting 80% of it, working the hard drive a lot. Thanks for any help.

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  • how to compare the checksums in a list corresponding to a file path with the file path in the operat

    - by surab
    Hi all, how to compare the checksums in a list corresponding to a file path with the file path in the operating system In Python? import os,sys,libxml2 files=[] sha1s=[] doc = libxml2.parseFile('files.xml') for path in doc.xpathEval('//File/Path'): files.append(path.content) for sha1 in doc.xpathEval('//File/Hash'): sha1s.append(sha1.content) for entry in zip(files,sha1s): print entry the files.xml contains <Files> <File> <Path>usr/share/doc/dialog/samples/form1</Path> <Type>doc</Type> <Size>1222</Size> <Uid>0</Uid> <Gid>0</Gid> <Mode>0755</Mode> <Hash>49744d73e8667d0e353923c0241891d46ebb9032</Hash> </File> <File> <Path>usr/share/doc/dialog/samples/form3</Path> <Type>doc</Type> <Size>1294</Size> <Uid>0</Uid> <Gid>0</Gid> <Mode>0755</Mode> <Hash>f30277f73e468232c59a526baf3a5ce49519b959</Hash> </File> </Files> I need to compare the sha1 checksum in between tags corresponding to the file specified in between the tags, with the same file path in base Operating system.

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  • Performance of SHA-1 Checksum from Android 2.2 to 2.3 and Higher

    - by sbrichards
    In testing the performance of: package com.srichards.sha; import android.app.Activity; import android.os.Bundle; import android.widget.TextView; import java.io.IOException; import java.io.InputStream; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.util.zip.ZipEntry; import java.util.zip.ZipFile; import com.srichards.sha.R; public class SHAHashActivity extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); TextView tv = new TextView(this); String shaVal = this.getString(R.string.sha); long systimeBefore = System.currentTimeMillis(); String result = shaCheck(shaVal); long systimeResult = System.currentTimeMillis() - systimeBefore; tv.setText("\nRunTime: " + systimeResult + "\nHas been modified? | Hash Value: " + result); setContentView(tv); } public String shaCheck(String shaVal){ try{ String resultant = "null"; MessageDigest digest = MessageDigest.getInstance("SHA1"); ZipFile zf = null; try { zf = new ZipFile("/data/app/com.blah.android-1.apk"); // /data/app/com.blah.android-2.apk } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } ZipEntry ze = zf.getEntry("classes.dex"); InputStream file = zf.getInputStream(ze); byte[] dataBytes = new byte[32768]; //65536 32768 int nread = 0; while ((nread = file.read(dataBytes)) != -1) { digest.update(dataBytes, 0, nread); } byte [] rbytes = digest.digest(); StringBuffer sb = new StringBuffer(""); for (int i = 0; i< rbytes.length; i++) { sb.append(Integer.toString((rbytes[i] & 0xff) + 0x100, 16).substring(1)); } if (shaVal.equals(sb.toString())) { resultant = ("\nFalse : " + "\nFound:\n" + sb.toString() + "|" + "\nHave:\n" + shaVal); } else { resultant = ("\nTrue : " + "\nFound:\n" + sb.toString() + "|" + "\nHave:\n" + shaVal); } return resultant; } catch (IOException e) { e.printStackTrace(); } catch (NoSuchAlgorithmException e) { e.printStackTrace(); } return null; } } On a 2.2 Device I get average runtime of ~350ms, while on newer devices I get runtimes of 26-50ms which is substantially lower. I'm keeping in mind these devices are newer and have better hardware but am also wondering if the platform and the implementation affect performance much and if there is anything that could reduce runtimes on 2.2 devices. Note, the classes.dex of the .apk being accessed is roughly 4MB. Thanks!

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  • Database checksum features - redundant? useful?

    - by Eloff
    Just about every mainstream DB has a feature to calculate checksums per page, per sector, or per record. Now for a DB that does full recover after any crash, like PostgreSQL, is a checksum even useful? There will be no data loss as long as the xlog is ok, no matter what kind of corruption happened to the data itself, as the redo log is replayed every committed transaction will be restored. So checksums are useless on restore. Doesn't the filesystem or disk keep checksums anyway to detect corruption? So unless the checksum is per record, all it does is tell you there is corruption - which the OS should be yelling at you the minute you try to read it - so useless in operation? I can't imagine how a checksum can be helpful in any sane database - but since they all use them - I'd say that's just failure of imagination on my part. So how is it useful?

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  • Determine whether .NET assemblies were built from the same source

    - by Clayton
    Does anyone know of a way to compare two .NET assemblies to determine whether they were built from the "same" source files? I am aware that there are some differencing utilities available, such as the plugin for Reflector, but I am not interested in viewing differences in a GUI, I just want an automated way to compare a collection of binaries to see whether they were built from the same (or equivalent) source files. I understand that multiple different source files could produce the same IL, and realise that the process would only be sensitive to differences in the IL, not the original source. The main obstacle to just comparing the byte streams for the two assemblies is that .NET includes a field called "MVID" (Module Version Identifier) the assembly. This appears to have a different value for every compilation, so if you build the same code twice the assembly will be different. A related question is, does anyone know how to force the MVID to be the same for each compilation? This would avoid us needing to have a comparison process that is insensitive to differences in the value of the MVID. A consistent MVID would be preferable, as this means that standard checksums could be used. The background behind this is that a third-party company is responsible for independently reviewing and signing off our releases, prior to us being permitted to release to Production. This includes reviewing the source code. They want to independently confirm that the source code we give them matches the binaries that we earlier built, tested and currently plan to deploy. We are looking for a process that allows them to independently build the system from the source we supply them with, and the compare the checksums against the checksums for the binaries we have tested. thanks

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  • What hash algorithms are paralellizable? Optimizing the hashing of large files utilizing on mult-co

    - by DanO
    I'm interested in optimizing the hashing of some large files (optimizing wall clock time). The I/O has been optimized well enough already and the I/O device (local SSD) is only tapped at about 25% of capacity, while one of the CPU cores is completely maxed-out. I have more cores available, and in the future will likely have even more cores. So far I've only been able to tap into more cores if I happen to need multiple hashes of the same file, say an MD5 AND a SHA256 at the same time. I can use the same I/O stream to feed two or more hash algorithms, and I get the faster algorithms done for free (as far as wall clock time). As I understand most hash algorithms, each new bit changes the entire result, and it is inherently challenging/impossible to do in parallel. Are any of the mainstream hash algorithms parallelizable? Are there any non-mainstream hashes that are parallelizable (and that have at least a sample implementation available)? As future CPUs will trend toward more cores and a leveling off in clock speed, is there any way to improve the performance of file hashing? (other than liquid nitrogen cooled overclocking?) or is it inherently non-parallelizable?

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  • CRC32 calculations for png chunk doesn't match the real one

    - by user2507197
    I'm attempting to mimic the function used for creating CRC's in PNG files, I'm using the autodin II polynomial and the source code from: http://www.opensource.apple.com/source/xnu/xnu-1456.1.26/bsd/libkern/crc32.c My tests have all been for the IHDR chunk, so my parameters have been: crc - 0xffffffff and 0 (both have been suggested) buff - the address of the IHDR Chunk's type. length - the IHDR Chunk's length + 4 (the length of the chunk's data + the length of the type) I printed the calculated CRC in binary, which I compared to the actual CRC of the chunk. I can see no similarities (little-big endian, reversed bits, XOR'd, etc). This is the data for the IHDR chunk (hexadecimal format): length(big endian): d0 00 00 00 (13) type: 49 48 44 52 data: 00 00 01 77 00 00 01 68 08 06 00 00 00 existing CRC: b0 bb 40 ac If anyone can tell me why my calculations are off, or give me a CRC32 function that will work I would greatly appreciate it. Thank-you!

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  • Webtest for binary content, how to ?

    - by Xaqron
    Assume a web page that returns binary content: http://localhost/website/Default.aspx?FileId=value and we have some files with known Ids and checksums (i.e. MD5). How it's possible to extract whole response and calculate it's check-sum via some visual studio webtest ?

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  • What hash algorithms are parallelizable? Optimizing the hashing of large files utilizing on multi-co

    - by DanO
    I'm interested in optimizing the hashing of some large files (optimizing wall clock time). The I/O has been optimized well enough already and the I/O device (local SSD) is only tapped at about 25% of capacity, while one of the CPU cores is completely maxed-out. I have more cores available, and in the future will likely have even more cores. So far I've only been able to tap into more cores if I happen to need multiple hashes of the same file, say an MD5 AND a SHA256 at the same time. I can use the same I/O stream to feed two or more hash algorithms, and I get the faster algorithms done for free (as far as wall clock time). As I understand most hash algorithms, each new bit changes the entire result, and it is inherently challenging/impossible to do in parallel. Are any of the mainstream hash algorithms parallelizable? Are there any non-mainstream hashes that are parallelizable (and that have at least a sample implementation available)? As future CPUs will trend toward more cores and a leveling off in clock speed, is there any way to improve the performance of file hashing? (other than liquid nitrogen cooled overclocking?) or is it inherently non-parallelizable?

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  • Windows command line ZIP extraction with checksum or similar ?

    - by Alan B
    What I need to do, at the command line, is: Extract the contents of a a ZIP archive. Change an arbitrary number of the extracted files. Repeat step 1, but because it is a huge archive, only extract the archived copies of the files changed in step 2 which is much faster. Ideally the extraction in step 3 would do something like a checksum on the files on disk and only extract those where the file in the archive has a different checksum. Or maybe compare the date changed stamp on the disk file. At the minute I use pkzipc.exe which is the command-line version of PkZip. I can't see a way to do it with this though. You can extract files from the archive that are newer than the disk files, but what I want is the opposite of that in a sense.

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  • Iterative / Additive MD5

    - by Andrew Robinson
    I need to generate a checksum over a dictionary. Keys and Values. Is there any simple way to accomplish this in an iterative way. foreach(var item in dic.Keys) checksum += checksum(dic[item]) + checksum(item); In this case, keys and values could be converted to strings, concatinated and then a single checksum applied over these but is there a better way? Ideally MD5 but other options could work. Using this to validate data that is passed over a couple of storage methods. The checksum is then encrypted along with some other information (using AES) so I am not horribly worried about an ideal, unbreakable checksum.

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  • Is INT the correct datatype for ABS(CHECKSUM(NEWID()))?

    - by Chad Sellers
    I'm in the process of creating unique customers ID's that is an alternative Id for external use. In the process of adding a new column "cust_uid" with datatype INT for my unique ID's, When I do an INSERT into this new column: Insert Into Customers(cust_uid) Select ABS(CHECKSUM(NEWID())) I get a error: Could not create an acceptable cursor. OLE DB provider "SQLNCLI" for linked server "SHQ2IIS1" returned message "Multiple-step OLE DB operation generated errors. Check each OLE DB status value, if available. No work was done. I've check all data types on both tables and the only things that has changed is the new column in both tables. The update is being done on one Big @$$ table...and for reasons above my pay grade, we would like to have new uid's that are different form the one's that we currently have "so users don't know how many accounts we actually have." Is INT the correct datatype for ABS(CHECKSUM(NEWID())) ?

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  • How to build the rpm package with SHA-256 checksum for files?

    - by larrycai
    In standard alone RHEL 6.4 rpm build environment, the rpm packages is generated with SHA-256 check sum, which is gotten by command rpm -qp --dump xxx.rpm [user@redhat64 abc]$ rpm -qp --dump package/rpm/abc-1.0.1-1.x86_64.rpm .. /opt/company/abc/abc/1.0.1-1/bin/start.sh 507 1398338016 d8820685b6446ee36a85cc1f7387d14537d6f8bf5ce4c5a4ccd2f70e9066c859 0100750 user abcc 0 .. While if it is build in docker environment (still RHEL6.4) the checksum is md5 UPDATE Use Ubuntu 14.04 as docker server, Redhat6.4 is the container inside [user@c1cbdf51d189 abc]$ rpm -qp --dump package/rpm/abc-1.0.1-1.x86_64.rpm .. /opt/company/abc/abc/1.0.1-1/bin/start.sh 507 1401952578 f229759944ba77c3c8ba2982c55bbe70 0100750 user abcc 0 .. If I checked the real file, the file is the same [user@c1cbdf51d189 1.0.1-1]$ sha256sum bin/start.sh d8820685b6446ee36a85cc1f7387d14537d6f8bf5ce4c5a4ccd2f70e9066c859 bin/start.sh [user@c1cbdf51d189 1.0.1-1]$ md5sum bin/start.sh f229759944ba77c3c8ba2982c55bbe70 bin/start.sh How I configure rpmbuild to let generated rpm file is SHA-256 based ?

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